• cron creates a username and password
• cron emails that username and password to a distribution list (could also use digital signage)
• cron deletes the previous days password

$user_array = array ( 	1  => 'q1',
							2  => 'q2',
							3  => 'q3',
							4  => 'q4'
						);

function CurrentQuarter(){
     $n = date('n');
     if($n < 4){
          return "1";
     } elseif($n > 3 && $n <7){
          return "2";
     } elseif($n >6 && $n < 10){
          return "3";
     } elseif($n >9){
          return "4";
     }
}
$current_user = $user_array[CurrentQuarter()];

Then as the "User" field, I did -

I simply created four users, q1, q2, q3 & q4

Then on the portal page, a little php to work out the quarter number, username field is then a hidden field.

It'll take you a while to add a user for each day though!